Charles, come on! You know that some hazards have more than 1 control!
Poultry slaughter example
I have VERY LITTLE control over what the animals are fed.............
The grower has to provide a flock sheet for the birds coming to the plant BEFORE they arrive-------------partial control
The other parts of this control are
1) only using approved growers
2) reviewing the flock sheets prior to the flock arriving and notifying CFIA if meds were used and no withdrawl noted
3) tissue samples that are done on a routine rotating schedule
No one "control" is adequate to deal with the hazard in this case
Or use freezing as another example
In poultry there are standards about how cold a bird must be over time an X/Y axis with an inversion
I can control water temp, but birds can't pick up too much water
I can control speed of chiller........but that's tied directly to the water temp
I can control the inverse temperature relationship
I cannot do those things with 1 control e.g. the water temp
I can think of a million examples when more than 1 control is needed to control a particular hazard